Washington, May 9 : Scientists have developed a novel gas sensor system, which makes it possible to monitor carbon dioxide in large areas, cost-effectively the first time.
Developed at the Helmholtz Centre for Environmental Research (UFZ) in Germany, the patented gas sensor is based on the principle of diffusion, according to which certain gases pass through a membrane faster than others.
Using a tube-like sensor it is possible to measure an average gas concentration value over a certain distance without influencing or distorting conditions in the measuring environment.
If such sensors are laid in a particular pattern, it is possible to calculate the concentration of a gas over an area. The measuring tube can therefore replace a large number of individual sensors, making it much cheaper than previous methods.
Potential fields of application for the membrane-based gas sensors ('MeGa') are environmental remediation and landfill monitoring. But in future, the technology could also be used to monitor the underground injection of carbon dioxide, gas pipelines or sewers.
The principle can also be used in liquids, so the probe is also useful for monitoring waterbodies (e.g. for observation of hydrogen sulphide formation), including groundwater, and for monitoring boreholes.
The slimline construction of the borehole and waterbody probe means that it can be used in gauges.
The (permanent) connection to the part above ground allows data capture/evaluation to take place while the probe is submerged.
Another potential field of application is process monitoring in water treatment or in the food industry, e.g. in breweries and dairies.
According to the researchers, in future, their system can also contribute to more intelligent ventilation of indoor spaces.
An excessive level of carbon dioxide leads to fatigue and health problems, while excessive ventilation means a waste of energy.
"With our membrane-based gas sensors it is for instance possible to have decentralised ventilation using a ventilator that is controlled by a gas sensor. The ventilation is then simply switched on if an adjustable threshold value is exceeded," said Dr Detlef Lazik from the UFZ.
The same principle can be used for monitoring dangerous substances in mining, in buildings and facilities or in tunnels.